1. Field of the Invention
The invention relates to a structure of a bending angle adjustment mechanism that is a mechanism for setting a maximum bending angle of the endoscope, and is for adjusting a moving amount, and a moving range of bending operation wires and chains, in a bending operation mechanism for performing a bending operation of a bending portion of the endoscope.
2. Description of the Related Art
A conventional flexible endoscope has been normally configured by an elongated insertion portion, and an operation portion that is connected to a proximal end portion of the insertion portion. The insertion portion is configured by an elongated flexible tube portion having flexibility, a bending portion and a distal end configuring portion being connected in sequence from a proximal end side. At the operation portion, a bending operation knob for performing a bending operation of the bending portion is placed. The bending operation knob is connected to a bending operation mechanism that is placed inside the operation portion. That is, a rotating shaft is integrally attached to the bending operation knob, and a rotating wheel (a sprocket) is integrally formed at the rotating shaft. A long member such as a chain is wound on the rotating wheel, and bending operation wires are further connected to both ends of the long member (chain or the like) via connecting members. The bending operation wire is inserted through and disposed inside the insertion portion, and is provided connectively between the bending operation mechanism and the bending portion. By a configuration as above, when the bending operation knob is rotationally operated normally and reversely, the chain and the operation wires are pulled and driven reciprocally via the bending operation mechanism, and a bending operation of the bending portion is realized.
Further, in the conventional flexible endoscope, setting of a bending angle differs according to each model depending on a use purpose, and therefore, the bending operation mechanism which is provided inside the operation portion of the endoscope is provided with a bending angle adjustment mechanism for restricting a maximum bending angle of the bending portion by adjusting a moving amount and a moving range of the long member for each model.
The bending angle adjustment mechanism is configured by having a stopper member that restricts movement of the bending operation wire and the connecting member, a screw member that performs positional adjustment by moving a position of the stopper member along a moving direction of the operation wire, a support member that is fixed to the fixing portion of the operation portion to support the stopper position adjusting screw member rotatably, and respective component members such as a partition wall that guides movement of the connecting member.
By the configuration as above, the maximum bending angle of the bending portion is restricted by movement of the connecting member being restricted by the stopper member, and the stopper member is moved in the moving direction of the operation wire to be positioned by the screw member, whereby setting of the bending angle of the bending portion is enabled.
Concerning the bending angle adjustment mechanism of this type in the conventional bending operation mechanism for an endoscope, bending angle adjustment mechanisms with various configurations have been conventionally disclosed by, for example, Japanese Patent Application Laid-Open Publication No. 2000-051146, Japanese Patent Application Laid-Open Publication No. 2007-054452, Japanese Patent Application Laid-Open Publication No. 09-238895, Japanese Patent Application Laid-Open Publication No. 2000-051148, Japanese Patent Application Laid-Open Publication No. 10-276966 and the like, and have been variously put into practical use.